Fix typo that breaks g++ cross detection on Debian.

mesonbuild/scripts/env2mfile.py

diff --git a/mesonbuild/scripts/env2mfile.py b/mesonbuild/scripts/env2mfile.py
index 9441402..645b953 100755
--- a/mesonbuild/scripts/env2mfile.py
+++ b/mesonbuild/scripts/env2mfile.py
@@ -197,7 +197,7 @@
     host_endian = data['DEB_HOST_ARCH_ENDIAN']
 
     compilerstems = [('c', 'gcc'),
-                     ('cpp', 'h++'),
+                     ('cpp', 'g++'),
                      ('objc', 'gobjc'),
                      ('objcpp', 'gobjc++')]
     infos = MachineInfo()